We know that dinosaurs had brains the size of hard-boiled eggs, while a comparatively massive brain has enabled us otherwise puny humans to dominate the globe. But how did we come to acquire our big brains? Human genetics, genome sequencing projects and cell biology have come together to provide a fascinating insight into the origins of our most important organ.

In this article, Dr Geoff Woods, a paediatrician working in clinical genetics, explains the clinical significance of microcephaly (small brain size) and how our increasing understanding of it might lead to neural stem cell therapies.

Dr Woods quickly noticed that he was seeing an unusual number of microcephalic children in his clinic: the incidence of what is formally designated autosomal recessive primary microcephaly (MCPH) is about 20 per million births among the Pakistani population, or ten times the rate normally seen in the UK. “We thought, they have been a relatively isolated population: we’ll go and look for the gene.”

Brains: learning by looking (and prodding)

The shape of the brain could tell us much about its function, but it may be the details that are important, says Professor Paul Fletcher. In his blog post, he guides us through the ‘craters’, ‘saddles’, ‘blisters’ and ‘pringles’ of the brain.

While phrenology has, for good reasons, fallen into disuse, there is still wide interest in the importance that the shape of the brain may have for its function and dysfunction. This is reflected in the fact that many neuroscientists spend a great deal of time examining variations in the folding and thickness of the brain surface.

You can also find out a lot about neurodegenerative disease from postmortem studies of the brains of patients. I recently highlighted a brilliant article by the Guardian’s Ed Pilkington, who visited the NFL brain bank and described the tragic story of an American Football star whose injuries took a toll on his later life.

When it comes to the dissections, it’s classic drama. We’re simultaneously grossed out and fascinated. The brain is an interesting organ because it’s something we maybe feel we shouldn’t see – we will never see our own brain after all. And despite our rapidly advancing scientific knowledge, there’s still so much mystery surrounding this squishy thing and how it produces and stores thoughts, ideas, emotions, experiences and memory. In reading (and watching) this, we and Pilkington are getting an insight into something few ever see.

You can tell just by summoning up an image of a caseless brain that an overall unwillingness to donate these organs comes from more than just inertia. I do not know how it feels to be religious, but in the absence of faith, it is impossible not to see this as the hull of your personality. It’s an interesting confrontation between atheism and a sense of identity, recognising how hard it is to view yourself dispassionately in death, as just an assortment of flesh.

The good and the bad of brain surgery

To get you in the mood, here’s a video from Wellcome Film of brain surgery in the 1930s:

Lobotomy has a bad name but it won its inventor a Nobel Prize. This article from our Big Picture magazine’s issue on Thinking looks at the history of brain surgery and the rise and fall of lobotomy as a legitimate surgical technique.

By the 1950s, the fact that its success rate was low and its side-effects common and severe, often leaving patients in a zombie-like state, led to its demise. The final nail in its coffin was the development of drugs, beginning with Thorazine, to treat mental disorders.

Surgical intervention in the brain does have its place in the medical armoury, however. But would you want to do it awake? Remarkably, this could help in removing brain tumours, as James Keidel explains in this article, which was shortlisted for the 2011 Wellcome Trust Science Writing Prize.

As Holly sits upright on the table, a psychologist shows her pictures of animals one by one. As she names the animals shown, Duffau periodically applies a small electrical current to her exposed brain. When this disrupts her ability to name the object, a small tag is placed on the brain’s surface, sparing this area if at all possible during the surgery. Throughout the operation, as the scalpel cuts deeper into the brain, this same procedure is repeated.

This post tells the story of Henry Molaison, who suffered from epilepsy and underwent experimental surgery in an attempt to cure his frequent and often disruptive seizures. Unbeknown to Henry at the time, the operation was set to become one of the most influential case studies in the history of neuroscience research.

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Wellcome Trust

The Wellcome Trust is a global charitable foundation dedicated to improving health by supporting bright minds in science, the humanities and social sciences, and public engagement. Read more.

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